Flexible electronics are expected to revolutionize the next generation of devices. Due to the high degree of flexibility of flexible electronics, they can be integrated into many different shapes. This flexibility and diverse integration options can provide for a large number of useful device configurations that would not be possible with the more rigid electronics that are fabricated based on silicon. Applications envisioned for flexible electronics include thin, flexible mobile devices, bendable and conformable displays, rollable and foldable flexible displays, and paper-like displays. Additionally, new forms of flexible electronic enable significant strain or stretch.
Some portions of such flexible electronics may be fabricated in solution. In addition, flexible substrates may be used in the fabrication of the flexible electronics. The flexible substrates enable fabrication by high speed printing techniques capable of generating electronic devices over large substrate at low cost. The flexible electronics also may be fabricated using independent fabricated components followed by assembly onto a single device substrate.
Fabricating flexible electronics that exhibit good electronic performance can be challenging. For example, fabrication techniques developed for the semiconductor fabrication industry are incompatible with some flexible materials. The temperatures used to generate high quality inorganic semiconductor components (for example, temperatures greater than 1000 degrees Celsius) are incompatible with many polymers, plastics and elastomeric materials. In addition, inorganic semiconductors are poorly soluble in the types of solvents that facilitate formation of the flexible electronics. While amorphous forms of silicon are fabricated using lower temperatures, it may not be compatible with the flexible electronic structure. Organic or hybrid organic-inorganic semiconductors can be processed at relatively low temperatures; however these materials do not form electronic structures with the performance capability needed for the next generation of flexible, foldable and bendable products.
Flexible electronics may be formed through incorporating inorganic semiconductor components into a polymer-based matrix. The flexible electronics can be fabricated on a rigid substrate or a flexible substrate. At one or more stages in the fabrication process, the flexible electronics is subjected to processing in solvents that are incompatible with the inorganic components. Therefore, polymer encapsulation of the inorganic device components has been suggested.
A challenge to large-scale production of the flexible electronics is the difficulty with separating the fabricated flexible electronics from the substrate on which the flexible electronics are fabricated. Mechanical removal may damage the flexible electronics by introducing stresses in the structure. Many chemical-based methods of separating the fabricated flexible electronics from the support substrate can cause damage to the flexible electronics.